build: remove AIX/ppc (32bit) dead code

[refack]

• also refactor OS400 detection

Refs: https://github.com/nodejs/node/pull/25447/files/36839defcfaf7c46435e16fb1f0da006f3ebe8ac#r247378894

/CC @nodejs/build-files @nodejs/platform-aix

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• documentation is changed or added
• commit message follows commit guidelines

[nodejs-github-bot]

@refack build started: https://ci.nodejs.org/blue/organizations/jenkins/node-test-pull-request-lite-pipeline/detail/node-test-pull-request-lite-pipeline/2257/pipeline

[refack]

AIX CI: https://ci.nodejs.org/job/node-test-commit-aix/20427/
AIX CI: https://ci.nodejs.org/job/node-test-commit-aix/20430/

[mhdawson]

@gireeshpunathil
@ThePrez

Can you two take a look and comment if you have any concerns.

[gireeshpunathil]

the configure error
21:24:54 gyp: Undefined variable aix_variant_name in /home/iojs/build/workspace/node-test-commit-aix/nodes/aix61-ppc64/node.gyp while trying to load

looks to be relevant here, as we moved a section containing aix_variant_name

[ThePrez]

LGTM, though I haven't tested with the changes. @dmabupt, can you please sanity-check?

[refack]

https://ci.nodejs.org/job/node-test-commit-aix/20476/
Latest change gets code to build, PTAL.

[richardlau]

There's similar code in node.gyp:

node/node.gyp

Lines 973 to 1000 in 098c2cc

	'variables': {'real_os_name': '<!(uname -s)',},
	'targets': [
	{
	'target_name': 'node_aix_shared',
	'type': 'shared_library',
	'product_name': '<(node_core_target_name)',
	'ldflags': [ '--shared' ],
	'product_extension': '<(shlib_suffix)',
	'conditions': [
	['target_arch=="ppc64"', {
	'ldflags': [
	'-Wl,-blibpath:/usr/lib:/lib:'
	'/opt/freeware/lib/pthread/ppc64'
	],
	}],
	['target_arch=="ppc"', {
	'ldflags': [
	'-Wl,-blibpath:/usr/lib:/lib:/opt/freeware/lib/pthread'
	],
	}],
	['"<(real_os_name)"=="OS400"', {
	'ldflags': [
	'-Wl,-blibpath:/QOpenSys/pkgs/lib:/QOpenSys/usr/lib',
	'-Wl,-bbigtoc',
	'-Wl,-brtl',
	],
	}],
	],

[refack]

CI: https://ci.nodejs.org/job/node-test-commit-aix/20503/

[dmabupt]

This line is not needed anymore --> https://github.com/nodejs/node/pull/25523/files#diff-259e627be3fafed9e9c10a7fcb26879eR970

[refack]

New AIX CI: https://ci.nodejs.org/job/node-test-commit-aix/20560/
New AIX CI: https://ci.nodejs.org/job/node-test-commit-aix/20561/ (✔️)
AIX + shared: https://ci.nodejs.org/job/node-test-commit-aix-shared-lib/256/ (⚠️ stable)

@dmabupt, can you verify this builds on IBM i (also with ./configure --shared)?

[refack]

It'll probably be evident in the CI, but we need to pass -maix64 to the linker as well as the compiler.

FTR, this is a sample error message from ld:

ld: 0711-736 ERROR: Input file /home/iojs/build/workspace/node-test-commit-aix/nodes/aix61-ppc64/out/Release/obj.host/genccode/deps/icu-small/source/tools/genccode/genccode.o:
 	XCOFF64 object files are not allowed in 32-bit mode.

[dmabupt]

New AIX CI: https://ci.nodejs.org/job/node-test-commit-aix/20560/
New AIX CI: https://ci.nodejs.org/job/node-test-commit-aix/20561/ ()
AIX + shared: https://ci.nodejs.org/job/node-test-commit-aix-shared-lib/256/ ( stable)

@dmabupt, can you verify this builds on IBM i (also with ./configure --shared)?

I have built Node.js on IBM i with / without the --shared option. Both builds passed.

[refack]

CI: https://ci.nodejs.org/job/node-test-pull-request/20291/
Resume: https://ci.nodejs.org/job/node-test-pull-request/20293/